Explanation
Step 1
Let
P1(1,-3)
slope=-1
Step 2
use the formula
[tex]y-y_1=m(x-x_1)[/tex]replacing
[tex]\begin{gathered} y-y_1=m(x-x_1) \\ y-(-3)=-1(x-1) \\ y+3=-x+1 \\ \text{subtract 3 in both sides} \\ y+3-3=-x+1-3 \\ y=-x-2 \end{gathered}[/tex]I hope this helps you
